Internal combustion engine with scavenging pump



April 27, 1943. V F. HUBER EIAL 2,317,772 INTERNAL COMBUSTION ENGINE WITH SCAVENGING PUMP Filed May 16, 1941 2 Sheets-Shee t 1 r INVENTORS FRITZ HUBER BY ANTON LENTZ IL- ATTORNE) April 27, 1943. HUBER ErAL 2,317,772

INTERNAL COMBUSTION ENGINE WITH SCAVENGING PUMP 7 Filed May 1a, 1941 2 Sheets-Sheet 2 '7 IINVENTORS FRITZ HUBER r w ANTON LENTZ ATTORA E)- ports.

Patented Apr. 27, 1943 UlED STATES PAraNroFi-ici: 7

INTERNAL COMBUSTION ENGINE wrrn SCAVENGING PUMP Fritz Huber, Mannheim, Heidelberg, Germany;

erty Custodian and Anton Lentz,

vested in the Alien Prop- Application May 16, 1941, Serial No. 393,720

In Germany February 10, 1940 13 Claims.

The present invention relates-to two-cycle internal combustion engines with scavenging pump. The object of the invention is, to prevent. admission of scavenging air and of combustible mixture into the cylinder of the scavenging pump or into the crank chamber to avoid fouling of the pump or the crank chamber by dust-laden air or ,dust containing combustible mixture and to pre-- vent that lubricating oil is drawn along into the cylinder and burnt therein.

According to the present invention the scavenge ing air, the gas and/or the combustible mixture, at the suction stroke of the scavenging pump, are sucked-in together or separately into one or several channels connecting the scavenging pump with the cylinder of the engine and serving merely as sluice. With this arrangement, the scavening air, the gas and/or the combustible mixture do not enter the crank chamber because the scavenging pump forces the air, the gas and/or the mixture from the connecting channels directly into the engine cylinder. The air in the crank chamber acts upon the scavenging air, gas and/or combustible mixture like an air piston. The channel according to the invention extends preferably from the admission ports in the cylinder to the lower part of the'crank cham ber; Its volume preferably corresponds approximately to the stroke volume of the engine cylin- 'der or is greater. The admission valve forthe admission of the fuel mixture is arranged in the ,channel preferably near the cylinder admission The introduction of the scavenging air into the channel is efiected according to whether gilt isdesired to be introduced in front of or ,be-

hind the fuel air mixture, I

If it is desired that the scavenging air is introduced in front of the combustible mixture, it is fed to the channel through an air valve inserted between the admission valve for the mixture and the admission ports to the cylinder, preferably directly to the admission ports of the cylinder.

The mixture valve is located at some distance from the admission ports. With this arrangement pure air flows first into.the cylinder which scavenges the residue from combustion, whereas the combustible mixture flows into' the cylinder space afterwards. In order to prevent'that at the next following compression stroke lubricating oil flowing out of the admission ports can flow up to the mixture admission valve and soil the same, the volume of the channel between the admission valve for the mixture and the admission ports is selected, according to the invention, about her which collects.

ducts theoil through channels: into collecting grooves in the crank chamber. .The oil coming 7 from the connecting rod bearing flows to'oil so great, that'it corresponds to the volume of the 55 .sharp diversion of flow in the against these :ing and=removing According to the invention anoil groove is 'arsections being displaced by 90". In the drawings l; designates the cylinder of two cycle gas engine, 2fthe' piscylinder in the range of its admission ports. Any oil which might enter intothis part of the-channei is sucked back together with the air in front of the piston bottom and is deposited in front of the combustible mixture.

of the channel connecting the scavengin pump and the cylinder ports is such that there is no vicinity of said ports and the fuel-air mixture admission valve so that there are no dead spaces in which lubrieating and/or fuel oil may accumulate.

If, however, directly in front of as well as directly behind the combustible mixture scaveng contact withthe lubricating oil in the crankchamber. The present invention has therefore also for. its object to 7 from the crank chamber. into, the channel. f This is attained according to theinvention by collect oil from,-the crank bearing. ranged underneath the pistonin the crank chamthe oil dropping off and concen'trifuging edges arranged atthe outer ends of the bearings wherefrom it is squirted intocatching grooves of approximately semi-circular shape and arranged in the cheeks of the crank shaft.

- These collecting grooves bring thegoil also into the lower part of the crank chamber, where it flows through passages into the collecting groove into which also the oil'fro'm the piston'is con I ducted.

The invention is illustrated, bywayof example in the accompanying drawings. an which Figs. 1 and2 show each one a section, these a slit-controlled The configuration are tightly embraced at their.

providemeans which effectively prevent; lubricating oil from penetrating l ton, 3 the crank shaft, 4 the scavenging slits, 5 the exhaust slit, 8 the cylinder cover, and I the crank chamber. The cylinder I or the scavenging slits 4 and the crank chamber I are connected by a channel 8, the upper end of which is connected, for instance, below the scavenging slits 4 with the cylinder I and the lower end of which is connected with the lower part of the crank chamber 1. The remaining part of the channel 8 leading to the scavenging slits l is formed by the cylinder itself. Near the connecting point to the cylinder the admission valve III for the air-gas mixture is arrangedin the channel 8 and connected with the gas mixture conduit I I. The volume of the channel 8 between the mixture admission valve III and the scavenging slits, corresponds approximately to the cylinder :space in the range of the scavenging slits. Above the mixture admission valve I0, approximately in the height of the scavenging slits .4, the admission valve I2 for fresh air is arranged on the channel 8 and mounted, in the form of construction shown, on the cylinder wall. At the lower endof channel 8, near its point of connection with the'- crank chamber 1, an air valve .213 is provided. The channel 8 can also be con'nectedwith the cylinder wall directly at the elevation of the scavenging slits 4. In thiscase the air valve I2 mayalso be mounted on the channel 8. The channel 8 need not be connected with the lower part of the crank chamber 1 but evidently may be connected also with another point thereof. Dash and dot line a in Fig. 1 indicates the travel of the scavenging air or of the residues from combustion respectively, line b the path of the fresh air following behind the mixture at the end of the scavenging step at much reduced scavenging pressure in the scavenging pump.

I4 designates the filling weights fixed on the cheeks I5 of the crank shaft 3, which, together with the cheeks, are in the form of discs. These discs are tightly embraced by the correspondingly constructed part I6 of the crank chamber 1 and sealed against the same by labyrinths II.

The gas engine has fresh oil lubrication, piston 2 being lubricated from point I8, main bearings I9 from point and connecting rod bearing 2I through oil pipe 22 and oil centrifuging rings 23.

The arrangement for collecting and discharging the lubricating oil separating from the path along which the piston travels consists of an oil catching groove 24 arranged underneath the path along which the piston moves, for instance in the crank chamber I, oil passages 25 and 28 and oil centrifuging rings 21 provided on the crank discs. The arrangement for. draining excess lubricating oil from the connecting rod bearing consists of oil centrifuging edges 28 provided on the outer ends of the connecting rod bearing 2|, passages 29 and semi-circular collecting grooves 30 arranged on the cheeks I 5. 3| designates an oil collecting groove provided in the lower part of the crank chamber I, whichgroove can be opened by an oil discharging screw 32.

The invention can be applied to gas engines as well as to engines which work with liquid fuel. It is immaterial whether into the channel only airor gas 'mixture or a mixture of air and power fluid is sucked.

We claim:

l. A two cycle internal combustion engine including, in combination, a scavenging pump, an engine cylinder, admission ports in said cylinder, a conduit connecting said pump and-said ports, a fresh air inlet means disposed in said conduit in the immediate vicinity of said ports,'and a fuel-air mixture admission means disposed in said conduit and spaced from said fresh air inlet means and from said ports.

2. A two cycle internal combustion engine including, in combination, a scavenging pump, an engine cylider, admission ports in said cylinder, a conduit connecting said pump and said ports, a fresh air inlet valve disposed in said conduit in the immediate vicinity of said ports, and a fuelair mixture admission means disposed in said conduit and spaced from said fresh air inlet means and from said ports, the portion of said conduit to which said fresh air inlet valve and said fuel-air mixture admission means are connected being substantially continuously directed and so designed that there is no sharp diversion and reversal of flow, a substantial part of said portion and also said fresh air inlet valve being disposed in the wall of said engine cylinder.

3. A two cycle internal combustion engine including, in combination, a scavenging pump, an

engine cylinder, admission ports in said cylinder,

a conduit connecting said pump and said ports, a fresh air inlet means disposed in said conduit spaced from said fresh air inlet means, the volume of said conduit between said mixture admission means and said pump amounting to at least the stroke volume of said cylinder.

5. A two cycle internal combustion engine including, in combination, a. scavenging pump, an engine cylinder, admission ports in said cylinder,

a conduit connecting said pump and said ports, a-

fresh air inlet means disposed in said conduit in the vicinity of said ports, a fuel-air mixture admission means disposed in said conduit and spaced from said fresh air inlet means, the volume of said conduit. between said mixture inlet means and said ports amounting to substantially the volume of said cylinder up to said ports.

' the vicinity of said ports, a fuel-air mixture admission means disposed in said conduit and spaced from said fresh air inlet means, crank discs, and individual sealing means disposed within said crank chamber adjacent to and eX- tending around said crank discs for catching the lubricating oil thrown off therefrom.

7. A two cycle internal combustion engine including, in combination, a crank chamber, a scavenging pump of the crank chamber type, an engine cylinder, admission ports in said cylinder, a conduit connecting said pump and said ports, a fresh air inlet means disposed in said conduit in the vicinity of saidports, a fuel-air mixture admission means disposed in said conduit and spaced from said fresh air inlet means, crank discs, and individual sealing means disposed a. fresh air inlet means disposed insaid conduit' in the vicinity of said ports, a fuel-airmixture? said crank chamber adjacent to and extendin'g around said crank discs for catching the lubriwithin said crank chamber adjacent to and extending around said crank discs for catching the lubricating oil thrown ofitherefrom, said sealing means comprising oil catching means disposed in the vicinity of said engine cylinder for catching lubricating oil emerging from said cylinder.

8. A two cycle internal combustion engine including, in combination, a crank chamber, a scavenging pump of the crank chamber type, an engine cylinder, admission ports in said cylinder, a conduit connecting said pump and said ports, a fresh air inlet means disposed in said conduit in the vicinity of said ports, a fuel-air mixture admission means disposed'in said conduit and spaced from said fresh air inlet means, crank discs, individual sealing means disposed within said crank chamber adjacent to and extending around said crank discs for catching the lubricating oil thrown ofl therefrom, and lubricating oil removing means in said crank chamber and connected for oil flow with said sealing means 3 means comprising 011 catching means disposed in the vicinity of said engine cylinder for catching lubricating oil emerging from said cylinder. and an oil catching groove in said crank chamber and connected for all now with'said'oil catching means.

11. Atwo cycle internal combustion engine including, in combination, a crank chamber, a

scavenging pump of the crank chamber type, an

engine cylinder, admission ports in-said cylinder.

' I a conduit connecting said pump and said ports, a

fresh air inlet means disposed in said conduit in the vicinity of said ports, a fuel-air mixture admission means disposed in said conduit and spaced from said fresh air inlet means, a connecting rod bearing membercomprising oil squirting edges, and crank discs comprising oil catching for removing the oil caught by said sealing means. .i 9. A two cycle internal combustion engine in- ,cluding, in combination, a crank chamber,- a

scavenging pump of the crank chamber. type,

an engine cylinder, admission ports in said cal- 'lnder, a conduit connecting said pump and said: 1

ports, a fresh air inlet means disposed in sa'id; conduit in the vicinity of said ports, a incl-g n mixture admission means disposed in saidcon -L duit and spaced from said fresh air inlet means,

crank discs, and individual sealing .means'disposed within said crank chamber adjacent to and extending around said crank discs for catching] the lubricating oil thrown oif therefrom, said sealing means comprisingan oilcatching groove facing oneend of said cylinderand collecting lubricating oil emerging from said cylinder.

10. A two cycle internal combustion engine admission means disposed int-said condiutand' grooves disposedoppositely to said edges and collecting the oil squirted therefrom.

- 12. A two cycle internal combustion engineincluding, in combination, a crank chamber,:a scavenging pump of the crank chamber type,an

engine-cylinder, admission ports in said cylinder,-

, a conduit, connectingsaid pump and said ports, a l freshair inlet means disposed in said-conduit in the vicinity of said a'iuel-air mixture ad- *"missio'n means disposed l'inj'said conduit and spaced from said fresh air inlet means, a crank disc having an oil centrifuging 'ring disposed at the-;ou-tside thereof,-*and acrank having an oil conduit communicating for .oilflow with said centrifuging ring andreeeiving .oiljtherefrom.

1 l3; A'two. cycle internal'combustion engine in cluding, in combination, -a crank chamber, a.

scavenging pump of thecrank 'chambertype, an

engine cylinder, admission'ports in; said cylinder, j i a conduitconnecting said'pumpand said ports, I a fresh air inlet means-disposed in said conduit in the vicinity of said ports, a fuel-air'mixture 'admission ineans disposed 'finf'i said conduit and spaced from said fresh "air; inletmeans, crank discshaying an oil squirtingedge, and individual spaced from 'said fresh" air'inlet meanazcrankjdiscs, individual sealing means disposed within eating oil thrown ofl therefrom, said sealing Y I sealing means disp sed within said crankchamf ber adjacentto and extending; around said crank discs for catching the lubricatinsoil thrown off therefrom, said sealing means comprising an oil collecting groove disposed oppositely to said edge and collectin the oil squirted therefrom.

v FRITZ'HUBER. ANTON LEN'IZ. 

